CODEWITHSUNDEEP
bashshellunixsedsh
ziga
ziga

Reputation: 109

Remove a particular pattern from string in shell

The original string is (according to my format)

"cf foo -J 12345 -z -macro TEST_IFDEFINE -macro THIS -macro THIS1 -macro THIS2"

In order to pass it to another script, I am trying to modify it into

"cf foo -J 12345 -z"

To achieve this I have written shell script as follows: 

string="cf foo -J 12345 -z -macro TEST_IFDEFINE -macro THIS -macro THIS1 -macro THIS2"
done=0
config="-cf"
name=""
for name in $string
do
  if [ $done -eq 1 ];then
    string=`echo $string | sed s/"-macro"//g`
    string=`echo $string | sed s/"$name"//g`
    echo "----->name: $name"
    macro_name="$macro_name -d $name"
    done=0
    echo "----->string: $string"
  fi
  if [ "$name" = "-macro" ];then
    done=1
    macro_def=1
  fi
done

From this code I am getting output is :

cf foo -J 12345 -z 1 2

Here, $name contains THIS1 and THIS2. But in script when I do

| sed s/"$name"//g`

it removes only

'THIS'

But keeping

1 2

along with original string. This means script is discarding only alphabets not numeric values in $name. Suggest me something to achieve this.

Upvotes: 1

Views: 3300

Answers (2)

chepner
chepner

Reputation: 532418

With extended patterns enabled, you can use a single parameter expansion.

$ shopt -s extglob
$ foo="cf foo -J 12345 -z -macro TEST_IFDEFINE -macro THIS keepme -macro THIS1 -macro THIS2 keepme"
$ echo "${foo//-macro +([[:alnum:]_])}?( )"
cf foo -J 12345 -z keepme keepme2

+([[:alnum:]_]) matches one or more letters, numbers, or _, which I assume to be the definition of a macro name. ?( ) removes the optional trailing space following a macro name. (Optional in the sense that a final -macro won't have a space after it.)

Upvotes: 2

fedorqui
fedorqui

Reputation: 290495

If you want to remove all the blocks of -macro WORD, just say so:

$ sed 's/\s-macro \S*//g' <<< "cf foo -J 12345 -z -macro TEST_IFDEFINE -macro THIS -macro THIS1 -macro THIS2"  | cat -vet -
cf foo -J 12345 -z$
  • \s-macro \S* matches space + -macro + space + a word.
  • sed 's/something//g' removes this something as many times as it occurs in the string.

Upvotes: 3

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